JPS60195084A - Apparatus for pulling semiconductor single crystal - Google Patents

Abstract

PURPOSE:To control the diameter of the growing single crystal in high accuracy, in the pulling of a single crystal from molten poly-crystals by Czochralski process, by suspending the single crystal with a flexible string. CONSTITUTION:The crucible 3 is placed in the furnace 1 furnished with the heater 4, and molten polycrystalline Si 5 is put in the crucible. A suspending member 20 holding the seed crystal 10 consisting of an Si single crystal is suspended through the hollow pulling shaft 7. The seed crystal is pulled up slowly from the molten polycrystalline Si 5 to effect the growth of the Si single crystal on the seed crystal 10. The bending of the suspending member 20 by the heat in the furnace can be prevented and the member 20 can be held constantly in vertical state by using a flexible string made of a heat-resistant bead-chain as the suspending member 20. Since the there is no excessive force applied to the load cell controlling the diameter of the single crystal 14, the control of the diameter can be carried out in high accuracy.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an improvement in a single-crystal semiconductor pulling apparatus for manufacturing semiconductor elements such as silicon.

[Technical background of the invention and its problems]

Generally, the Czochralski method is known as one of the methods for manufacturing single crystal silicon for semiconductor devices such as transistors.

Conventionally, in an apparatus used for producing this type of single crystal silicon, as illustrated in FIG. This crucible 3 is surrounded by a hot zone 4 made of a heater and a heat insulator, and the crucible 3 heats the polycrystalline silicon to which necessary impurities have been added inside the crucible 3 to melt the silicon 5. A hollow pulling shaft 7 that is rotated up and down by a pulling mechanism 6 is exposed inside the body 1, a hanging support member 8 made of a rod is inserted into this pulling shaft 7, and a seed holder 9 is inserted into the lower end of this hanging support member 8. What about that? 3
A seed crystal 10 is connected to the seed crystal 10 to be brought into contact with the silicon melt 5 in the furnace, and the upper end of the suspension member 8 is suspended from the tip of a load cell 11 for weight measurement installed on the upper part of the pulling shaft 7. W formed by sealing the insertion portions of the body 1, push-up shaft 2, and pull-up shaft 7 with reseals 12 and 13, respectively.
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In this type of pulling device, when pulling up the seed crystal 10 that has been brought into contact with the silicon melt 5 in the crucible 3, all of the hanging support members 8 that hold the seed crystal 10 are made to follow the upward rotational movement of the pulling shaft 7. By using the hollow pulling shaft 7, the suspension support member 8 and the load cell 11 are prevented from being subjected to extra force such as sliding or rotation due to the seal 13, and crystal growth is prevented at the tip of the seed crystal 1θ during the pulling process. The diameter of the single crystal silicon 14 is controlled by measuring the weight of the single crystal silicon 14 with a high-resolution load cell 1.

However, in such a conventional pulling device, during long-term use, the hollow pulling shaft 7 or the hanging support member 8 may bend due to the heat inside the furnace body 1, and as a result, extra force is applied to the load cell 11. This causes noise, which not only makes it impossible to accurately control the diameter, but also prevents the pulling shaft 7.
Various inconveniences have occurred, such as the fact that it is not always possible to pull up the melt in the direction perpendicular to the surface of the melt in the crucible 3 due to deflection due to bending of the hanging support member 8.

[Purpose of the invention]

The present invention has been made based on the above-mentioned circumstances, and its purpose is to provide a single-crystal semiconductor pulling device that can pull up a hanging support member without vertical swinging at all times. There is a particular thing.

[Summary of the invention]

In order to achieve the above-mentioned object, the present invention connects a seed crystal to be brought into contact with the semiconductor melt in the tube to a hanging support member inserted into a hollow pulling shaft, and connects this hanging support member to the pulling shaft. In a single-crystal semiconductor pulling apparatus, the single-crystal semiconductor is obtained by suspending the crystal from a diameter control device installed at the top and measuring the weight of the crystal, and pulling the single-crystal semiconductor by following the upward rotational movement of the pulling shaft. It is characterized in that the supporting member is formed from a flexible strip such as a ball chain instead of a conventional rod-like material.

[Embodiments of the invention]

The present invention will be described below with reference to an embodiment shown in FIG. In the illustrated embodiment of the present invention, parts having the same configuration as those of the conventional device shown in FIG.

That is, in the apparatus of the present invention shown in FIG. 2, the hanging support member 20 inserted into the hollow pulling shaft 7 is made of a ball chain (wire may also be used) made of a heat-resistant material such as stainless steel, molybdenum, or ceramics. It is made up of flexible strips consisting of.

Therefore, according to the present device described above, since the hanging support member is formed of the bead chain 20, even if the pulling shaft 7 is slightly bent due to the heat inside the furnace body 1 due to the flexibility of the bead chain 20, the bead chain The seed crystal 10 connected to the seed crystal 20 via the seed holder 9 is always kept perpendicular to the surface of the silicon melt 5 in the crucible 3, making it possible to perform pulling without shaking.

In addition, a load cell 1 is provided between the chain 20 and the pulling shaft 7.
No force occurs that would impede the measurement of the weight of the single crystal 14 by 1.

〔Effect of the invention〕

As explained above, the present invention uses a flexible strip such as a bead chain as the hanging support material that is suspended from a load cell that measures the crystal weight and controls the diameter, which is different from the conventional method. Since the suspension member itself does not bend and is not affected by the bending of the pulling shaft, the seed crystal can always be pulled perpendicular to the semiconductor melt. It has excellent practical effects, such as no generation or generation and good diameter control.

[Brief explanation of the drawing]

FIG. 1 is a schematic explanatory diagram showing a conventional single-crystal semiconductor pulling apparatus, and FIG. 2 is a schematic explanatory diagram showing an embodiment of the single-crystal semiconductor pulling apparatus according to the present invention. 1°/° furnace body, 3... Crucible, 5... Silicon melt, 6... Pulling mechanism, 7... Pulling shaft, 9... Seed hoyv/, 1o... RFL crystal, 17...Load cell, 14...Single crystal silicon, 2o...Hanging support material. Applicant's agent Patent attorney Takehiko Suzue Figure 1 Figure 2

Claims (2)

[Claims] (1) Diameter determined by measuring the weight of the crystal in which a seed crystal to be brought into contact with the semiconductor melt in the rudder is connected to a hanging support member inserted into a hollow pulling shaft, and this hanging support member is placed above the pulling shaft. In a single-crystal semiconductor pulling device that obtains a single-crystal semiconductor by suspending it from a control device and pulling it up following the upward rotational movement of the pulling shaft, the hanging support member is formed of a flexible strip. A device for pulling single crystal semiconductors. (2) The apparatus for pulling a single crystal semiconductor according to claim 1, wherein the flexible strip is made of a chain made of a heat-resistant material.